Apparatus for producing a honeycomb body

ABSTRACT

The present invention relates to an apparatus for producing a honeycomb body, which comprises a roll part for supplying a thin metal flat sheet via several rolls; a part for measuring the length of feed of the flat sheet which is fed through said roll part for supplying a flat sheet; a roll part for supplying a corrugated sheet to overlap the same onto said flat sheet via several rolls; a winding roll of a honeycomb body which is made by folding the overlapping flat and corrugated sheets in feed into a roll; a part for measuring the rotation angle of said winding roll; and a control part, which is connected respectively to said part for measuring the length and said part for measuring the rotation angle, wherein said control part controls the amount of winding of a honeycomb body by receiving and computing the measurement values therefrom.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an apparatus for producing a honeycomb body used in catalytic purification of exhaust gas of an internal combustion engine. In particular, the present invention relates to an apparatus for producing a honeycomb body, which can produce precise dimensions for accurately inserting said honeycomb body of a spiral form into a metal outer shell, wherein said honeycomb body is made by folding a flat sheet and a corrugated sheet into a roll.

[0003] 2. Description of the Related Art

[0004] In general, as for the support for catalytic purification of exhaust gas, one with an outer shell of a cylindrical metal material is used, wherein a honeycomb body is inserted and joined thereto. At that point in time, if the outer diameter of the honeycomb body is less than the inner diameter of the outer shell, the outer shell and the honeycomb may become separated due to improper joining therein. On the other hand, if the outer diameter of the honeycomb is larger than the inner diameter of the outer shell, it is impossible to insert the honeycomb into the outer shell without damaging the shape thereof. Even if a forceful insertion can be made with ensuing damages to the shape, it would be followed by non-uniformity with respect to overall joining with major problems for permeability.

[0005] For this reason, it is necessary to produce a honeycomb with a certain set of dimensions, and in this regard the methods used up to now can be classified into two major types. The first method involves direct control by measuring the diameter or radius of the honeycomb body in roll (hereinafter referred to as a method of measuring outer diameter, Japanese Patent No. 4-371234). The second method involves indirect control over the length of the strip used during the winding process of a honeycomb body (hereinafter referred to as a method of measuring length).

[0006] Of these methods, the method of measuring outer diameter involves a honeycomb body, produced by a winding process, which is of a warped shape in spiral, not in a round form. Hence, even if a honeycomb body were to be produced, which perfectly matches the inner diameter of an outer shell at one point of measurement, it would be considerably larger or lesser than the inner diameter of the outer shell at some other points of measurement. Consequently, it is very difficult to insert a honeycomb body into the outer shell, although it may potentially be capable of accurate insertion into the outer shell. Moreover, even if a standard for accurate insertion into the outer shell could be made by many trials and errors, there still is the disadvantage of necessarily carrying out another set of trials and errors due to the changes in the dimensions of the outer shell. Therefore, this method may be applied to mass production of a small number of limited product types, yet it is inappropriate for small-lot production of a variety of product types.

[0007] The method of measuring length obviously brings about many trials and errors due to its indirect control method. All in all, however, it has a fatal flaw. This is a problem relating to tension in effect during the winding process. It is necessary to control the tension to the flat sheet or corrugated sheet during the winding process in order to increase its structural tightness and mechanical strength. In this case, if the tension being controlled changes to the slightest extent, the size of the cell changes. As the size of the cell changes, the length of the strip used to produce honeycomb bodies of the same dimensions changes. Consequently, it becomes difficult to control the dimensions of a honeycomb by using the length of the strip used in the overall process. Therefore, in using the method of measuring length, it is impossible to consistently produce honeycomb bodies with a certain set of dimensions if the reproduction is not carried out perfectly with respect to additional conditions of tension from the start of the winding process to its end.

SUMMARY OF THE INVENTION

[0008] In so far as it relates to an apparatus for producing a honeycomb body used in catalytic purification of exhaust gas of an internal combustion engine, the objective of the present invention lies in providing an apparatus for producing a honeycomb body, which can produce precise dimensions for accurately inserting the same into a metal outer shell, wherein said honeycomb body in spiral is made by folding a flat sheet and a corrugated sheet into a roll.

[0009] In order to achieve the aforementioned objective, the present invention, in its basic technical concept, comprises a roll part for supplying a thin metal flat sheet via several rolls; a part for measuring the length of feed of the flat sheet which is fed through said roll part for supplying a flat sheet; a roll part for supplying a corrugated sheet to overlap the same onto said flat sheet via several rolls; a winding roll of a honeycomb body which is made by folding the overlapping flat and corrugated sheets in feed into a roll; a part for measuring the rotation angle of said winding roll; and a control part which controls the amount of winding in a roll of a honeycomb body by means of computing the measurement values from said part for measuring the length and said part for measuring the rotation angle.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a drawing, which illustrates an apparatus for producing a honeycomb body according to the present invention.

[0011]FIG. 2 is a flowchart of the main program for length control of the control part according to the present invention.

[0012]FIG. 3 is a flowchart for the speed control subroutine program of the control part according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0013] Below, the present invention is described in detail by means of an embodiment as illustrated in attached figures.

[0014] As shown in FIG. 1, the present invention, in its basic technical concept, comprises a roll part 10 for supplying a thin metal flat sheet 10 a via several rolls; a part 20 for measuring the length of feed of the flat sheet 10 a which is fed through said roll part 10 for supplying a flat sheet; a roll part 30 for supplying a corrugated sheet 30 a to overlap the same onto said flat sheet 10 a via several rolls; a winding roll 40 of a honeycomb body (H) which is made by folding the overlapping flat and corrugated sheets (10 a and 30 a) in feed into a roll; a part 50 for measuring the rotation angle of said winding roll 40; and a control part 60 with pre-storage set values (inner circumference of an outer shell), which is connected respectively to said part 20 for measuring the length and said part 50 for measuring the rotation angle, wherein said control part 60 controls the amount of winding for a honeycomb body by receiving and computing the measurement values therefrom.

[0015] In the present invention, as shown in FIG. 1, the honeycomb body (H) is made by supplying a flat sheet 10 a via a roll part 10 for supplying a flat sheet to the winding roll 40; further supplying a corrugated sheet 30 a via a roll part 30 for supplying a corrugated sheet to the winding roll 40; and overlapping said flat and corrugated sheets (10 a and 30 a) at the winding roll 40 and folding the same into a roll in the form of a honeycomb. At that point in time, the values measured respectively at the part 20 for measuring the length and the part 50 for measuring the angle are sent to the control part 60. Then, the control part 60 stops the winding operation of the winding roll 40 when the computed value from the measurements equals the pre-stored value (i.e., the inner circumference of an outer shell), after which leads to completion of one honeycomb body (H).

[0016] After the completion of the honeycomb body (H), flat and corrugated sheets (10 a and 30 a) are cut, after which the winding operation is once again initiated. For the sequence of cutting the flat and corrugated sheets (10 a and 30 a), it is preferable to cut the corrugated sheet first, then followed by a flat sheet. At the time of cutting the corrugated sheet, the amount of the corrugated sheet has a major effect on the outer circumference of the honeycomb body (H). As such, it is preferable to cut the corrugated sheet by closely adhering it, to the maximum extent possible, to the honeycomb body in a roll. In this way, after first cutting the corrugated sheet, the winding axis is additionally rotated to a certain degree. Then, the flat sheet is fixated by using a spot welding machine to prevent unfolding of a honeycomb body, after which the flat sheet is cut. In this manner, the winding operation of the honeycomb body is thus completed.

[0017] In close examination of the present invention, the idea for the present invention came about from the observation that the shape of a honeycomb body is not of a round form but of a warped spiral, and that it cannot be inserted into an outer shell with precision by means of a method of measuring outer diameter. In other words, in order to adhere the outer most wall of a honeycomb to the outer shell in its entirety by precisely inserting the honeycomb body into the cylindrical outer shell with a round cross-section, the critical point in such situation is that the outer circumference of a honeycomb body in a roll must equal the inner circumference of the outer shell, irrespective of the outer diameter. However, it is impossible to directly measure the outer circumference of a honeycomb body, and therefore, the method of measuring the amount of a strip consumed per rotation of a winding roll is being used.

[0018] To explain in detail, the method involves equally dividing one rotation (i.e., 360°) of a winding roll into N units according to the desirable precision level, and then measuring the length of a strip consumed per rotation during the operation of 1˜N times. Even after the rotation of 360°, if the length thereof is less than the preset value (i.e., the value corresponding to the length of the inner circumference of an outer shell), it is reset to N=0 for repeating the above operation. When reaching the desirable length during this operation, the operation is then stopped at that point.

[0019] In using this method, the precision thereof can become considerable according to the degree of equal division per rotation of a winding roll or a device for measuring the length. Moreover, by this method, a honeycomb body with precise adhesion to the outer shell can be produced.

[0020] At the part 20 for measuring the length, the length of the flat sheet 10 a consumed during the process of folding the honeycomb body (H) into a roll is measured accumulatively from the start, and the values thereof are turned over to the control part 60. As the winding operation progresses, the roller 21 for measuring the length rotates, and the encoder 22 for measuring the length, which is connected to said roller, calculates the length of the strip so consumed therein. In order to prevent slipping, without sensing the progression of the strip, the roller (21) for measuring the length should preferably be of rubber or a material with similar adhesion. By way of sufficient pressure, the roller has the role of preventing such slippings. Further, in order to minimize the effect of the operation of measuring the length as above on the control of tension to the honeycomb body, the load cell 11 for sensing tension, as shown in FIG. 1, is installed immediately posterior to the part 20 for measuring the length.

[0021] As for the part 50 for measuring the angle as above, for the purpose of operation simplification, the point, breaking from the winding roll 40, where it is level with the ground, is set to 0°. From this point, the winding operation is initiated. After starting the winding operation, the encoder 51 for measuring the angle, installed onto the winding roll 40, measures the rotation angle of the winding roll 40 and transfers the measurement values to the control part 60 (refer to FIG. 1).

[0022] The control part 60, being the core technology of the present invention, comprises a set-up part which sets the length of the outer circumference of the honeycomb body (H) to be produced and then pre-enters those set values; an input part which receives the values read by said part for measuring the length 20 and the part 50 for measuring the angle; a computation part which carries out the computation for stopping the winding operation at a desirable length based on the values entered from said input part; and an output part which transmits the signals from said computation part to the winding roll 40.

[0023] At the computation part, as shown in FIG. 2, the stopping point for the winding operation is calculated by comparing the length of the strip consumed per rotation of a winding roll with the pre-entry set values. In other words, the computation part reads the following values: the value (N) of equal division for one rotation by a winding roll, which is a set value corresponding to the initial condition of the winding operation, the rotation speed (V_(s)) of the winding roll at the start of the operation, and the final value for the length of the outer circumference of the honeycomb body (L_(f)). Moreover, the computation part calculates the interval (d) of equal division of rotation angle, which in turn is used in the measurement of the actual rotation speed (V) of a winding roll and the amount of winding with respect to a strip. As set above, the N^(th) number of steps is produced per rotation of winding roll axis. As such, the rotation angle (D) of a winding roll, the steps (n), etc. are initialized to 0 so that the variable (LP(n)), which stores the length of a strip in a roll, prior to one rotation per respective step, and the current position of the winding axis are recognized as 0°. From the start of the winding operation, as it progresses from step 1 to n, during its progression from the prior position to the current position to the extent of one rotation, the amount of a strip (L) in a roll is calculated per angle of equal division of the aforementioned setting. This value is computed by limiting the total length (LP(n)) of the strip consumed prior to one rotation of the current position after the start of the operation from the total length (L(n)) of the strip consumed until the current position after the start of the operation. If the length (L) of the strip consumed in one rotation is less than the final set value of length of the outer circumference (L_(f)), it proceeds to the next step (n=n+1). Then, in the case of completion of the N^(th) step operation, it proceeds until 1˜n steps. Meanwhile, the total consumption amount (L(n)) of the strip per respective step as read is substituted to the total consumption amount LP(n)) of the prior step, after which it is restarted from step 1. If the length (L) of the strip consumed by one rotation is more than the final value of length (L_(f)) of the outer circumference, the winding operation is terminated thereby.

[0024] For reference, the symbols used in the flowchart of FIG. 2 are as follows:

[0025] N: the value of equal division per rotation by a winding roll;

[0026] n: step (integer);

[0027] V: actual rotation speed of the winding roll;

[0028] V_(s) : rotation speed of the winding roll at the start of the operation;

[0029] S: a factor related to the rotation speed of the winding roll;

[0030] L: the consumption amount of a strip until step n from prior to 360°;

[0031] L_(f): the final length of outer circumference;

[0032] L(n): the total consumption amount of a strip until step n after the start of the operation;

[0033] LP(n): the total consumption amount of a strip until one rotation prior to step n from the start of the operation;

[0034] d: the interval for equal division of the rotation angle used in the measurement of the amount of winding of a strip; and

[0035] D: the actual rotation angle of the winding roll.

[0036] On the other hand, if necessary, in order to precisely control the amount of winding, the subroutine program of FIG. 3 can be used to increase the rotation speed of the winding roll as the amount of wind is increased (i.e., as the radius of the honeycomb is increased). In this way, errors, which can be generated from the delay in computation time of the program, could be minimized.

[0037] In this manner, the amount of winding can be more accurately controlled by means of speed control. Further, by increasing the rolling speed from the start to the middle of the operation, the production time per unit of a honeycomb can be reduced, which in turn can be applied to the operation of mass production.

[0038] As shown above, the apparatus for producing a honeycomb body according to the present invention has the effect of producing a honeycomb body of the optimal size, which can be accurately inserted into the outer shell by means of measuring the amount of a strip consumed in the continuous production of honeycomb bodies during the winding operation.

[0039] Further, it is anticipated that the present invention would have the effect of total inspection by means of controlling the size of a honeycomb body into appropriate size by using a relatively simple program.

[0040] As for the conventional method of measuring outer diameter, or the method of measuring length, many trials and errors were necessary for producing honeycomb bodies of one size. However, the present invention can produce honeycomb bodies of uniform size without such trials and errors, which in turn leads to an increase in productivity in term of its application to small-lot production of a variety of product types.

[0041] Further, the present invention has the effect of reducing production time per unit of a honeycomb body by means of controlling the rolling speed according to the increase in the radius of winding of the honeycomb body, which in turn can be applied to the operation of mass production. 

What is claimed is:
 1. An apparatus for producing a honeycomb body, which comprises a roll part for supplying a thin metal flat sheet via several rolls; a part for measuring the length of feed of the flat sheet which is fed through said roll part for supplying a flat sheet; a roll part for supplying a corrugated sheet to overlap the same onto said flat sheet via several rolls; a winding roll of a honeycomb body which is made by folding the overlapping flat and corrugated sheets in feed into a roll; a part for measuring the rotation angle of said winding roll; and a control part, connected respectively to said part for measuring the length and said part for measuring the rotation angle, from which said control part receives the measurement values for computation to control the amount of winding of a honeycomb body.
 2. The apparatus for producing a honeycomb body according to claim 1, comprising a load cell for sensing tension of a flat sheet, which is folded into a roll at the posterior of said part for measuring the length.
 3. The apparatus for producing a honeycomb body according to claim 1, wherein said part for measuring the length comprises a roller for measuring the length of a flat sheet as the winding operation of a flat sheet proceeds, and an encoder for measuring the length, which is connected to said roller for measuring the length, to calculate the length of a strip consumed therein.
 4. The apparatus for producing a honeycomb body according to claim 3, wherein said roller for measuring the length is of an adhesion material.
 5. The apparatus for producing a honeycomb body according to claim 1, wherein said control part comprises a set-up part which sets the length of the outer circumference of the honeycomb body to be produced for pre-entry of said set values; an input part which receives the values read at said part for measuring the length and said part for measuring the angle; a computation part which carries out the computation to stop the winding operation at a desirable length based on the values inputted from said input part; and an output part which transmits the signals from said computation part to the winding roll. 